1. Field of the Invention
The present invention relates to a method of mounting a measuring device for measuring the relative positions of two objects, such as, the bed and the carriage of a machine, wherein a graduation of an embodiment of measure is scanned without contact by a scanning device. The invention also relates to an apparatus for carrying out the method.
2. Description of the Prior Art
In known methods of the above-described type, machines, for example, machine tools, are equipped with position measuring devices which make it possible to digitally read as a position measurement value the position of the carriage relative to the bed of the machine, or to supply the measurement values to a numeric control and to use them in the control in the known manner for controlling the machine.
The machines as well as the position measuring devices have tolerances which may lead to errors which, in the final analysis, are considered machine errors. To be able to determine the resulting total error, the machine manufacturer measures the finished machine tools provided with position measuring devices by means of a comparative measuring system having an equally high accuracy.
Interferometric measuring devices are suitable for this purpose. Also suitable are measuring devices which operate in accordance with the grid scanning method if they have an accuracy which is at least one order of magnitude higher than the measuring device with which the machine to be measured is equipped.
The deviations determined by the comparative measuring device can be further processed in various different ways. However, the compensation of this deviation is not subject matter of this application and is already discussed in many prior publications, so that this compensation is not discussed herein.
It is, therefore, the primary object of the present invention to provide a method of the above-described type which makes it possible to mount a correspondingly accurate position measuring device with sufficient accuracy on a machine to be measured.